iSCSI: SCSI Response Hdr - Sense Data Length

[Michael Schoberg <michael_schoberg@cnt.com>]

A question concerning the iSCSI - SCSI Response headers (op-0x21).  When the
target sends it with a DataSegmentLength > 0, it must automatically include
a two-byte sense data header preceding any response data.  This means all
response data will be offset by this two byte header even if the
sense-length is zero.  Why wasn't the sense data length put in the byte 20
range of the response (currently marked reserved)?  This would've avoided
the extra work for initiators to have to handle response data for this PDU
type differently from the others.  Essentially, this forces another header
handler on the initiator side for the two header bytes describing the sense
data length.